Process for converting alkyl sultones to alkene sulfonic acids

ABSTRACT

Alkyl sultones are converted to alkene sulfonic acids by hydrolysis with a critical amount of water (i.e., 5 to 35 percent) optionally followed by dehydration and rehydrolysis, each step increasing the yield of alkene sulfonic acids.

,[22] Filed:

United States Patent [191 Sweeney et al.

[111 3,887,611 1 June 3, 1975 PROCESS FOR CONVERTING ALKYL SULTONES TOALKENE SULFONIC ACIDS [75] Inventors: William A. Sweeney, Larkspur;

Ralph House, San Pablo, both of Calif.

[60] Division of Ser. No. 215,191, Jan. 3, 1972, Pat. No. 3,845,114,which is a continuation-in-part of Ser. No. 33,948, May 1, 1970,abandoned. 1

[52] US. Cl. 260/513 R; 260/504 R [5l] Int. Cl. C07c 143/16 [58] Fieldof Search 260/513 R, 504 R [56] References Cited 6 UNITED STATES PATENTS3,376,336 4/1968 Stein et al. 260/513 R I 3,423,453 1/1969 Baumann etal. 260/513 R Primary ExaminerLe0n Zitver Assistant ExaminerNicky ChanAttorney, Agent, or F irm-G. F. Madgeburger; John Stoner, Jr.; J. TeddBrooks [57] ABSTRACT Alkyl sultones are converted to alkene sulfonicacids by hydrolysis with a critical amount of water (i.e., 5 to 35percent) optionally followed by dehydration and rehydrolysis, each stepincreasing the yield of alkene sulfonic acids.

7 Claims, No Drawings PROCESS FOR CONVERTING ALKYL SULTONES TO ALKENESULFONIC ACIDS CROSS-REFERENCE TO RELATED APPLICATION This is a divisionof application Ser. No. 215,191, filed Jan. 3, 1972, now US. Pat. No.3,845,114. which is a continuation-in-part of application Ser. No.33,948, filed May 1, 1970, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention is concerned with the field of synthetic detergentcompositions, and more particularly with a process for preparingmixtures of olefin sulfonates containing major amounts of alkenesulfonates.

2. Description of the Prior Art Olefin sulfonates are primarily producedby sulfonation of olefins with sulfur trioxide. However, this method ofsulfonation followed by hydrolysis and neutralization of the productproduces a mixture containing approximately 50 percent by weight each ofhydroxy alkane sulfonates and alkene sulfonates. The importance of highalkene sulfonate contents in olefin sulfonate detergents is known in theart.

Several processes have been proposed for obtaining high concentrationsof alkene sulfonates from the reaction of an olefin and S In oneprocess, the sulfonation step is modified by complexing the S0 with amoderator such as dioxane (J. Am. Oil Chem. Soc., 42, 873 (1965)) ortrialkylphosphate (Ind. & Eng. Chem., Prod. Res. and Dev., 2, 229(1963)). These processes suffer from the drawback of having a moderatorpresent which must be recovered and recycled for economic operation.

Another process which has been proposed for obtaining an increasedrecovery of alkene sulfonic acid involves modification of the hydrolysisstep. For example, Canadian Patent 775,589 teaches the hydrolysis of theolefin-S0 reaction product with an alkoxide. A disadvantage of thismethod is that the alkoxides are expensive.

In the sulfonate surfactant field, significant commercial activitycenters around the production and shipment of alkylaryl sulfonic acids.The sulfonate producers thus can make a single, liquid product which isinexpensive to ship because it is not diluted by water, which isnormally present after a neutralization step. However, it also allowsthe customer latitude either to use the acids directly in certainapplications or to neutral ize them with a variety of bases.

Olefin sulfonates are not generally known in the anhydrous acid form.The usual direct sulfonation product contains a large proportion ofsultone which is inactive in either the acid or neutralized form. Thepresence of sultones also makes the product solid at room temperatuare.Hydrolysis of the sulfonation product after water addition and beforeneutralization is known in the art; however, the amount of water whichis taught to be added (two parts of one part of sulfonate) isundesirably high for subsequent shipping, or for use in non-aqueoussystems.

SUMMARY OF THE INVENTION A novel process for the hydrolysis of alkylsultones is provided. In this process the sultones containing from 10 to24 carbon atoms are hydrolyzed in the presence of a certain minor butcritical amount of water (i.e. 5

to 35 percent) to obtain a useful mixture of alkene sulfonic acids andhydroxyalkane sulfonic acids.

In a particularly useful embodiment of the invention the alkyl sultonesare present in a reaction mixture along with alkene sulfonic acid andother materials in an olefin sulfonate mixture which is commonly derivedby the reaction of 50:, with suitable olefins. Subsequent dehydration ofthe hydrolysis product will convert the hydroxyalkane sulfonic acid toalkyl sultones. Each repetition of the hydrolysis and dehydration stepsreduces the alkyl sultone content of the mixture by about 50 percent andthus increases the alkene sulfonic acid content by a correspondingamount. The procedure can be repeated until the desired level of alkenesulfonic acid is obtained. After the desired level of alkene sulfonicacid content is obtained, the final product mixture may be directly usedin commerce or may be saponified with a base to produce the sulfonatesalts suitable for use in detergent compositions.

DETAILED DESCRIPTION OF THE INVENTION Olefins suitable for conversion tosulfonic acids in accordance with the present invention includestraightchain alpha olefins from wax cracking, straight-chain alphaolefins produced by Ziegler polymerization of ethylene, straight-chaininternal olefins prepared by catalytic dehydrogenation of normalparaffins, and straight-chain internal olefins prepared bychlorination-dehydrochlorination of normal paraffins. The olefins maycontain from 10 to 24 carbon atoms, usually 13 to 22 carbon atoms, andpreferably 14 to 20 carbon atoms per molecule.

In addition, the process of the present invention may be practiced onalkyl sultones, wherein the hydrocarbon portion of the molecule containsfrom 10 to 24 carbon atoms, usually 13 to 22 carbon atoms, andpreferably 14 to 20 carbon atoms per molecule. US. Pat. Nos. 3,164,608and 3,164,609 describe processes for obtaining sultones from olefins byreaction with S0,, and subsequent distillation or filtration. Thesultones formed as a result of an SO -,:olefin reaction may also beseparated from a cold neutralized product by extraction. Thesetechniques and procedures are known in the art.

In a preferred embodiment, however, the process of the present inventionis conducted on sulfonated olefins containing alkyl sultones and alkenesulfonic acids as the major components as well as a lesser proportion ofdisulfonated product. When olefins are sulfonated in accordance with themethod as described below, the sulfonated product, commonly calledolefin sulfonate, usually contains from about 20 to 60 percent by weightof alkene sulfonic acid and from about to 40 percent of alkyl sultone;normally, the original sulfonation product will contain from 30 to 40percent alkene sulfonic acid.

The amount of S0 utilized in the sulfonation of the olefins may bevaried but is usually within the range of 0.95 to 1.25 mols of 50;, permol of olefin and preferably in the range 1:1 to 1.2: 1. Greaterformation of disulfonated products is observed at higher sO zolefinratios. Disulfonation may be reduced by carrying the sulfonationreaction only to partial conversion of the olefin for example, by usingSO :olefin ratios of one or less and removing the unreacted olefin by adeoiling or vaporization process.

In order to obtain a product of good quality, the S employed in thesulfonation reaction is generally mixed with an inert diluent or with amodifying agent. Inert diluents which are satisfactory for this purposeinclude air, nitrogen, 80,, dichloromethane, etc. The volume ratio of S0to diluent is usually within the range of 1:100 to 1:1. In some cases,the reaction of olefin with S0 can be carried out under subatmosphericpressure without a diluent. Modifying agents sometimes employed with80;, include dioxane, trialkyl phosphates, etc.

Hydrolysis as used herein is contemplated to mean the cleavage of thesultone ring to give a mixture of alkene sulfonic acid and hydroxyalkanesulfonic acid. In the situation wherein the sultones are obtained in anolefin sulfonation mixture, then after sulfonation, the sulfonatedolefins are treated with water in a sufficient amount to hydrolyze themajor portion of the sultone present. In general, on a weight basis, ithas been found desirable to use from 5 to 25 percent, and preferably topercent of water based on the weight of sultone, although in theinterests of complete hydrolysis somewhat larger amounts up to about 35percent may be used. The use of too little water during hydrolysisresults in oligomerization and a subsequent loss in yield of alkenesulfonic acids.

On the other hand, hydrolysis can be effected with much larger amountsof water present than those specified above, but an undesirable productis formed. If the hydrolyzed acid is to be used directly in commerce, itis expensive to ship the dilute acid. If attempts are made to dehydrateit according to the procedures of this invention, the product will forman intractable gel.

Additionally, there is a surprising increase in solubility of the sodiumsulfonate salts of acids obtained by the hydrolysis procedure describedherein as compared with conventional products.

The hydrolysis reaction is conducted at temperatures sufficient to causethe reaction of water and sultone for example, in the range of from 100to 200C and preferably 140 to 170C. In general, the reaction timerequired is from about one-half hour to 20 hours and preferably 2 to 8hours. At higher temperatures of reaction, generally shorter times arenecessary.

The time required for hydrolysis in this process is longer than thatrequired in the known processes for hydrolyzing a 20 to 50 percentaqueous sulfonate solution by either acidic or basic catalysis.Apparently different chemical steps are involved, leading to a differentproduct. In the present process it is believed that the sultonesisomerize before opening thereby giving a product containing mostly4-hydroxyalkane sulfonate and very little of the normal 3-hydroxyalkanesulfonates.

If the repetitive process is used to increase the alkene sulfonic acidcontent, all of the sultones need not be bydrolyzed during any givenhydrolysis step, but rather only the major portion need be reacted sinceafter several cycles essentially all of the sultones will have beenconverted to alkene sulfonic acids.

The extent of the hydrolysis reaction can be followed by severaldifferent analytical techniques. One method is the cold titration withcaustic. That is, an acid number is determined by titration of a portionof the original feed, and, as the reaction proceeds, titrations are madeon small aliquots until there is little or no change in acid number withincreasing hydrolysis time.

During both the hydrolysis and dehydration steps (see below), the NMRspectrum should be run when the water content is lower than about 10percent to ensure that the oligomerization reaction as described incopending application U.S. Ser. No. 858,097 is not occurring. In somecases it may be advantageous to obtain a mixed product from bothhydrolysis and dimerization.

Dehydration in the present context includes both removal of unboundwater (drying) and the chemical loss of water from a hydroxy sulfonicacid to form sultone. The latter step will not occur until the former issubstantially complete, and therefore criticality of the dehydrationstep primarily involves processing during the final stages ofdehydration. Conditions specified for dehydration, then, apply to thesecond stage when the water content has been reduced below about 5percent.

Dehydration of the hydrolyzed sulfonated olefins may be accomplished byseveral different methods. Surprisingly, dehydration of the hydrolyzedmixture only slightly affects the alkene sulfonic acids present. Thatis, dehydration converts the major portion of the hydroxyalkane sulfonicacid to alkyl sultones with little or no loss of alkene sulfonic acidcontent.

Examples of the dehydration methods include: heat ing at temperaturesabove C, heating at temperatures below 100C under subatmosphericpressure or with an inert gas sweep, and by adding an azeotropic agentand distilling out an aqueous azeotrope. Suitable azeotropic agentsinclude but are not limited to benzene and xylene.

During dehydration, it is necessary that the timetemperature history bemild enough to prevent dimerization. (See copending application Ser. No.858,097.) For example, at 100C up to 1 to 2 hours reaction time may beemployed without unsuitable dimerization occurring, whereas at C only afew minutes of heating can be employed for dehydration withoutdimerization. The pressure on the system during the dehydration step isusually 1 /2 atmospheres or less. It is preferred that the temperaturebe maintained below 100C with subatmospheric pressure. For example,6080C is a most preferable range. It has been found that mostsatisfactory results are obtained by operating at pressures below 100 mmof mercury'and preferably below 200 mm of mercury.

The dehydration step will require heating the hydroxyalkane sulfonicacid-containing mixture for a period of time necessary to removeessentially all of the water previously added. This will usually requirefrom about 0.05 to 10 hours and more preferably from about 0.1 to 2hours. Preferred times are 0.2 to 1.0 hours. The step of dehydration canbe followed by measuring the amount of water distilled off the reactionproduct, or it may be followed by cold caustic titration of the reactionmixture. When the second method is used, heating of the reaction mixtureis continued until the acid number shows little or no decrease withincreasing timev At this time, a major portion of the hydroxyalkanesulfonic acid will have been reconverted to sultone. At the same timeNMR spectra may be obtained to ensure that dimerization is notoccurring.

The hydrolysis and dehydration steps may then be re' peated as often asrequired to give as a final product, alkene sulfonic acid essentiallyfree of hydroxyalkane sulfonic acid. In general, three or more cyclesare re quired. For example, three cycles on a typical air-SO alphaolefin reaction product would yield a product containing from about 90to 95 percent by weight of alkene sulfonic acid.

It the final product is to be a sulfonic acid-water mixture, the lastprocess step will be hydrolysis as described above. If the final productis to be a neutralized salt, the hydrolyzed acid mixture will beneutralized in the usual manner with alkali or alkaline earth oxides,hydroxides, carbonates, etc., or with ammonia or organic amines.Alternatively, the final sultone hydrolysis step may be included in orsubsequently to the neutralization. This will convert the small amountof sultone remaining into the salt of mixed sulfonic acids. This can bedone, for example, by heating the final reaction mixture with causticwithin the range of 80200C for periods of from a few minutes up to aboutan hour. As the temperature increases, the time necessary for finalhydrolysis decreases. At about 150C, times within the range of 0.1 to0.5 hours were found sufficient.

The neutralized alkene sulfonate surface-active material may berecovered from the product obtained as described above by drying as in aspray drier, or in a drum drier, or it may be used as a concentratedaqueous solution. The dried material is usually combined with variousbuilders, well known in the detergent art, to give a heavy-dutydetergent formulation. These builders include, among others, sodiumphosphate, so-

dium silicate, sodium sulfate, and carboxymethylcellulose. The productsof the present invention are particularly useful in liquid detergents.For this use, the aqueous solution may be mixed with other surfaceactivematerials, such as linear alkylbenzene sulfonates, alcohol sulfates, andalcohol ethoxy sulfates. Hydrotropic agents, such as xylene sulfonate,or solvents may also be added to improve the clear point of theresulting liquid formulation.

In general, additional compatible ingredients may be incorporated intothe compositions of the present invention when used as detergents toenhance their detergent properties. Such ingredients may include, butare not limited to, anti-corrosion, anti-redeposition, bleaching andsequestering agents, optical whiteners (area at 3.4-3.7 ppm and certainorganic and inorganic alkali and alkaline earth salts, such asphosphates, inorganic sulfates, carbonates, or borates, and the organicsalts of the amino polycarboxylic acids, e.g. trisodium salt of nitrilotriacetic acid, tetrasodium salt of ethylenediamine tetraacetic acid,etc.

The following examples illustrate the application of the process of thisinvention to provide olefin sulfonate mixtures in the acid formcontaining a minor amount of water and further processing to obtainmixtures con taining a maximum amount of alkene sulfonate.

EXAMPLE 1 Sulfonation of l-hexadecene The sulfonation unit which wasemployed consisted of a 5 mm ID. 3-foot, jacketed falling film reactorequipped with an inlet weir for the olefin feed, a central 3 mm O.D.sulfur trioxide-air inlet tube, followed by a 1% X 4 inch post reactortube. The reactor was continuously charged with l-hexadecene at a rateof 4.36 grams per minute. Simultaneously there'was added 1.87 grams perminute of S diluted to 5 percent by weight in air. The temperature ofthe outer surface of the reactor wall was maintained in the range of-65C by circulating cooling water in the jacket. The sulfonation productwas cooled and chilled to 0C over a period of 2 hours. The productweighed 739 grams.

A lO-gram portion of the acid/sultone product was analyzed by coldneutralization (room temperature) with 1.3 mmoles/gram of NaOH inaqueous alcohol followed by complete hydrolysis and neutralization at95C. This analysis showed the initial presence of 34 percent sulfonicacid and 66 percent sultones. The sodium salt obtained was de-oiled bythree extractions with petroleum ether from a 75 percent alcoholsolution to obtain about 0.5 percent by weight oil. This indicates thatboth the original sulfonation and the hydrolysis steps weresubstantially complete.

An IR spectrum of the reaction product showed the presence of bothsultone and sulfonic acid.

An NMR spectrum showed similar evidence of the mixture of sultones andunsaturated sulfonic acid.

EXAMPLE 2 Hydrolysis of l-hexadecene-SO Reaction Product a. With alimited amount of water The unneutralized reaction product of Example 1,grams, and 10 grams of water was placed in a Fischer- Porter bottleequipped with a magnetic stirrer. The mixture was heated to 150C andstirred at this temperature for 6 hours.

At the end of this time both [R and NMR spectra showed that most of thesultone had been hydrolyzed. The IR spectrum showed the unsaturatedsulfonic acid peaks at 1700, 1165, 1040, 965, and 910 cm .No appreciablesultone bands at 1330-1360, 940, 895, or 810-880 were found. The NMRspectrum showed a large peak at 5.2-5.4 ppm for vinyl protons, a smallpeak at 4.4-4.7 ppm representing about 9 percent sultone, and a peak at3.4-3.8 ppm for the carbinol proton of hyroxyalkane sulfonic acid. TheNMR ratio of second functionality to sulfonic groups, determined fromthe expression,

area at i. ii.6 ppm) area at 5.2-5.6 ppm area at 2.6-3.3 ppm is 1.2 forthis product.

Most of this acidic product, 52.8 grams, was dissolved and neutralizedwith NaOH in percent aqueous ethanol. An insoluble salt (1.24 grams, 2.7percent of active) was removed by filtration, and an oil (3.01 grams,6.8 percent of active, identified as a 1,4-sultone by IR spectrum) wasrecovered by five extractions with petroleum ether followed byevaporation of the ether. The neutralization equivalent of this materialwas 3.08 mmoles/gram, as is, or 3.6 on a dry basis. The desalted,de-oiled active was dried to a free-flowing powder containing 1.4percent by weight water. The IR spectrum was the same as the sulfonatesalt of Example 1 except for a larger 965 cm band (from trans internaldouble bonds) and a broad hydroxyl band centering at 3450 cm.

The sodium sulfonate salt was titrated with a standardized solution ofcationic agent (l-lyamine 1622) to give an equivalent weight of 334.Analysis for alkene sulfonate content by analytical hydrogenation showedit to be 67 percent alkene sulfonate.

From these analyses it was concluded that the original hydrolyzed acidcontained about 8 percent sultone,

62 percent alkene sulfonic acid, 28 percent sulfonic acid, and 2 percentinorganic acids.

b. With an intermediate amount of water The acid product of Example 1,30 grams, was heated as in Example 20 with grams of water at 160C for 6hours. During this time the mixture remained in a gelled condition evenat the high temperature. Consequently, little or no stirring wasaccomplished. An IR spectrum of the product indicated that hydrolysishad occurred, but practical separation of the acid from the gel wasimpossible.

c. With a large amount of water 2b was repeated except that grams ofacid product and 40 grams of water were heated at 150C for 1 hour. TheIR spectrum showed that hydrolysis was complete. The material wasneutralized with NaOH (requiring 3.9 mmoles/gram on a dry basis). Thesodium sulfonate was desalted (removing 0.5 percent of insolublematerial), de-oiled (removing 1.9 percent oil), and dried to 1 percentwater content. The IR spectrum of the material was quite similar to thatof Example 2a except that the hydroxyl band was broader and centered at3400 cm. This example shows that hydrolysis occurs much faster when alarge amount of water is present.

EXAMPLE 3 Oligomerization of the Hexadecene-SO Reaction Product The acidreaction product from Example 1, 50

grams, was heated in a round bottomed flask atl50-l53C for 2% hours. Atthe end of this time, the viscosity of the heated material wasconsiderably greater than that of the starting material.

An infrared spectrum showed strong adsorptions at 1700, 1165, 1040, 910cm, all of which are typical of aliphatic sulfonic acids. The absence ofadsorption bands at 1330-1360, 895 and 810-880 cm showed that thesultone originally present in the feed stock had all been converted. Theabsence ofa 965 cm'l adsorption band showed that there were no1,2-disubstituted double bonds, i.e., all alkene-sulfonic acid wasconverted.

A nuclear magnetic resonance (NMR) spectrum had adsorption at 2.9-3.2ppm, typical of aliphatic sulfonic acids. The absence of any bonds at4.4-4.6 ppm and at 5.0-5.9 ppm also indicated complete conversion of thesultone and the absence of any 1,2-disubstituted double bonds,respectively.

A neutralization equivalent analysis required 0.0032 mols of base pergram of product.

The product was shown to have 2.3 percent water by a Karl Fishertitration.

The remainder of the product was converted to the sodium salt and wasthen desalted by precipitation from 70 percent aqueous ethanol anddeoiled by five extractions of this solution with petroleum ether. Theprecipitate was analyzed for Na SO and the extract was concentrated.This procedure showed the presence of 1.5 percent (wt.) oil and 0.4percent sodium sulfate in the reaction mixture. The IR spectrum of thesulfonate salt was typical of the IR spectrum of olefin sulfonate salts,except there was no adsorption at 965 cm", i.e., there were no doublebonds of the transconfiguration.

This example shows that heating the sulfonate reaction product in theabsence of added water leads to a substantially different product asdescribedin copending application Ser. No. 858,097.

EXAMPLE 4 Hydrolysis of S0 Reaction Product Obtained by Low Conversionof l-Hexadecene EXAMPLE 5 Hydrolysis of Pure Sultone Hexadecyl sultone(10 g.), recrystallized twice and containing about percent of the1,3-isomer and 30 percent of the 1,4-isomer was hydrolyzed as in Example2a with 2 g. water at C for 6 hours. It remained fluid throughout thehydrolysis and at the end had an infrared spectrum equal to that ofExample 2a.

EXAMPLE 6 Viscosity of Sulfonate-Water Mixtures Various mixtures (2.5g.) of the acidic sulfonation product of Example 1 with water wereplaced in 5 ml. sealed glass ampoules with a small stainless steel balland heated over a number of hours from 60C to C. Visual observation ofviscosity was as follows:

Water Content, 7: Viscosity at 170C 5 Fluid l0 Fluid 20 Sli htly Fluid30 Ge led 50 Fluid EXAMPLE 7 Solubility of Sodium Sulfonates Clearsolution temperatures of the desalted, deoiled sulfonates of Examples 2aand 20 were determined for 25 percent solutions in distilled water asfollows:

Low water product of Example 2a 41C High water product of Example 2c 45CEXAMPLE 8 Conversion of the Hydrolyzed Sulfonate to a Methyl Ester Thehydrolysis product of Example 2a (2.13 g.) was dissolved in 250 ml. ofdiethyl ether. Then diazomethane formed by the base-catalyzeddecomposition of N- methyl-N-nitroso-p-toluenesulfonamied [ReferencezRec. Tran. Chim. 73, 229 (1954)] was bubbled into the either solutionuntil the solution had a persistent yellow color. The ether was removedto yield 1.85 g. of yellow oil whose infrared spectrum showed peaks at1360, 1170 and 995 em", all of which are characteristic of methylaliphatic sulfonate esters, plus a small band at 900 cm from the 7percent 1,4-sultone remaining and a small band at 3560 cm from thehydroxyalkane sulfonate.

EXAMPLE 9 Drying the Hydrolyzed Sulfonate The hydrolyzed product ofExample 2a (32.9 g.) was heated under vacuum with a nitrogen sweep in arotary evaporation placed in a water bath at 40C until the remainingproduct weighed 27.3 g. Typical changes occurred in the infraredspectrum associated with loss of water from an aliphatic sulfonic acid;namely, decrease in the broad absorptions at 3200-3500 cm and 1120-1230cm and increase in the ratio of peaks at 900 and 1040 cm. However, therewas no indication of sultone formation (no absorption at 1350 and 825cm) and the neutralization equivalent did not change. A similarexperiment was made in the same way but with several 50 m1 portions ofbenzene being added to help remove the water by azeotrope formation. Thesame result was obtained.

EXAMPLE 10 Dehydration of Hydrolyzed Sulfonate Portions of the driedproduct of Example 9 were heated and neutralization equivalents obtainedas follows:

These neutralization equivalents correspond to the formation of about 40percent sultone compared with the original sultone content in Example 1of 66 percent. The higher neutralization equivalent obtained at thehigher temperature and longer time is evidence of some oligomerizationoccurring.

Infrared spectra of these samples all showed considerable l,4-sultoneformation as evidenced by peaks at 900, 825 and 530 cm. No 1,3-sultonewas observed. The trans internal olefin peak at 965 cm" was stillpresent. Analysis of the infrared spectrum of the methyl esters of theseproducts (prepared as in Example 8) confirmed the presence of about 40percent 1,4- sultone and showed that no hydroxyalkane methyl sulfonatewas present.

EXAMPLE ll Rehydrolysis of Dehydration Product Dehydration product 12.1g.), prepared as in Example 10c, plus 2.41 g. water was heated at 160Cfor 6 hours. Infrared analysis showed that hydrolysis of the l,4-sultoneoriginally present giving 4-hydroxy-1- sulfonate was substantiallycomplete. The amount of 4-hydroxyalkane sulfonate present was shown tobe 21 percent by subsequently passing the material through the dryingand dehydrating steps of Examples 9 and using the loss in neutralizationequivalent and infrared of the methyl ester as analytical tools.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that modifications and variations of the illustrativeexamples may be made in the practice of the invention within the scopeof the following claims.

What is claimed is:

1. A process for maximizing the alkene sulfonic acid content of astraight chain 10 to 24 carbon sulfonated olefin which comprises thesteps of a. hydrolyzing the alkyl sultone present in the sulfonatedolefin to alkenesulfonic acid and hydroxyalkanesulfonic acid bycontacting the sulfonated olefin with from 5 to 25 percent of waterrelative to the weight of the alkyl sultone at a temperature of from 100to 200C for a period of from about onehalf hour to about 20 hours, and

b. dehydrating the product of (a) to convert the hydroxyalkanesulfonicacid produced in (a) by heating the product and distilling off the waterproduced by the resulting dehydration of the hydroxyalkyl sulfonic acidto alkyl sultone, and

c. hydrolyzing again as in (a).

2. Process according to claim 1 wherein steps (b) and (c) are repeatedat least one additional time.

3. The process of claim 2 wherein in (a) the water is employed in anamount of from 10 to 20 percent by weight relative to the alkyl sultone.

4. The process of claim 1 in which the temperature is from to C.

5. The process of claim 1 in which the sulfonated olefin contains from13 to 22 carbon atoms.

6. The process of claim 1 in which the water is removed by distillationof a suitable azeotrope.

- 7. A process for maximizing the alkene sulfonic acid content of asulfonated olefin of 10 to 24 carbon atoms which comprises alternaterepetition of steps (b) and (c) of claim 1 until at the final completionof step (c) the product is essentially free of hydroxyalkane sul- UNITEDSTATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO.3 ,887,6ll

DATED 1 June 3, 1975 INVENIOMS)I William A. Sweeney and Ralph HouseltmcmmmdmmenmamwmsmmeEmw-mmmfiwpmmtmdmmsmdLflwmPmmtmehmdwcmmcmdasflmwnbflow Col. 1, line 59, "of one" should read -to one-.

Col. 7, line 1, after "percent" (second occurrence) insert--hydroxyalkane--.

Col. 8, line 60, "either" should read --ether-.

Col. 10, line 36 (Claim 3), "claim 2" should read --claim l-.

Signed and Sealed this fourteenth Day of October 1975 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (nmmissioner ofPaterzts and Trademarks

1. A PROCESS FOR MAXIMIZING THE ALKENE SULFONIC ACID CONTENT OF ASTRAIGHT CHAIN 10 TO 24 CARBON SULFONATED OLEFIN WHICH COMPRISES THESTEPS OF A. HYDROLYZING THE ALKYL SULTONE PRESENT IN THE SULFONATEDOLEFIN TO ALKENESULFONIC ACID AND HYDROXYLKANESULFONIC ACID BYCONTACTING THE SULFONATED OLEFIN WITH FROM 5 TO 25 PERCENT OF WATERRELATIVE TO THE WEIGHT OF THE ALKYL SULTONE AT A TEMPERATURE OF FROM100* TO 200*C FOR A PERIOD OF FROM ABOUT ONE-HALF HOUR TO ABOUT 20HOURS, AND B. DEHYDRATING THE PRODUCT OF (A) TO CONVERT THEHYDROXYALKANESULFONIC ACID PRODUCED IN (A) BY HEATING THE PREDUCT ANDDISTILLING OFF THE WATER PRODUCED BY THE REUSLTING DEHYDRATION OF THEHYDROXYALKYL SULFONIC ACID TO ALKYL SULTONE, AND C. HYDROLYZING AGAIN ASIN (A).
 1. A process for maximizing the alkene sulfonic acid content ofa straight chain 10 to 24 carbon sulfonated olefin which comprises thesteps of a. hydrolyzing the alkyl sultone present in the sulfonatedolefIn to alkenesulfonic acid and hydroxyalkanesulfonic acid bycontacting the sulfonated olefin with from 5 to 25 percent of waterrelative to the weight of the alkyl sultone at a temperature of from100* to 200*C for a period of from about one-half hour to about 20hours, and b. dehydrating the product of (a) to convert thehydroxyalkanesulfonic acid produced in (a) by heating the product anddistilling off the water produced by the resulting dehydration of thehydroxyalkyl sulfonic acid to alkyl sultone, and c. hydrolyzing again asin (a).
 2. Process according to claim 1 wherein steps (b) and (c) arerepeated at least one additional time.
 3. The process of claim 2 whereinin (a) the water is employed in an amount of from 10 to 20 percent byweight relative to the alkyl sultone.
 4. The process of claim 1 in whichthe temperature is from 140* to 170*C.
 5. The process of claim 1 inwhich the sulfonated olefin contains from 13 to 22 carbon atoms.
 6. Theprocess of claim 1 in which the water is removed by distillation of asuitable azeotrope.